NASA opened a $150,000 Lunar Grounding Challenge to find engineering solutions preventing astronauts from accumulating hazardous static electricity during moonwalks.
The Physics of Lunar Tribocharging and Plasma Buildup
NASA aims to put astronaut boots at the lunar south pole in 2028 during the Artemis 4 or 5 missions, marking the first landing mission since Apollo 17 in 1972. Simulations suggest that tribocharging, which is the electric-charge transfer between two objects, and plasma charging from ambient regional gas combine to build up significant electric charges on spacesuits.
This problem is severely compounded when entering lunar shadows and permanently shadowed regions. These deeply cratered areas receive no direct sunlight.
An excess of negatively charged electrons accumulates compared with positive ions in these dark zones. The risk materializes specifically when an astronaut returns to the spacecraft.
The lander maintains a slight positive charge, generating an acute hazard as the highly negatively charged astronaut approaches the vehicle. An electrical arc could then damage spacesuits, spark fires in the oxygen atmosphere of a spacecraft, or deliver electrical shocks.
A Mars simulation in 2018 was reportedly derailed due to a crew experiencing electrical issues, so this problem is not unprecedented.
Technical Requirements for the 2028 Artemis Missions
Submissions for the $150,000 competition are due Jan. 15. The challenge targets designs that safely discharge the astronaut and their spacesuit prior to physical contact with the lander.
NASA outlined strict engineering constraints for potential solutions. The hardware must remain small in terms of mass, volume, and power. It also needs to operate reliably amidst the extreme temperature swings of the lunar surface.
The technology must support as many as four extra-vehicular activities, commonly known as moonwalks, spanning operations over a duration as long as 10 days.
Suspended lunar dust and heavy dust buildup on a suit in these environments significantly increase arcing lengths. This debris allows sparks to jump across larger gaps than they would in a clean vacuum.
Therefore, the chosen solution must actively prevent a sudden arc from contacting the outer pressure garment or the lander. NASA did not release a target date in its press release for when the final production technology would be available for operational deployment.
The Timeline for the 2030s Lunar Base
The challenge progresses through multiple phases. These include initial concept design, concept refinement following technical reviews, and a final selection.
The broader exploration schedule centers on establishing a long-term moon base. This base is planned to be largely ready for sustained astronaut missions in the 2030s, provided agency schedules hold.
